1. Field of the Invention
The present invention relates to a disc drive apparatus that is utilized for recording information such as music in a disc and reproducing recorded information, particularly, relates to a disc drive apparatus that is suitable for recording and reproducing a magneto-optical disc contained in a predetermined cartridge such as a mini-disc (MD).
2. Description of the Related Art
A disc such as MD (mini-disc), CD (compact disc) and DVD (digital versatile disc or digital video disc) has been well known as a recording medium for musical information until now. An apparatus for reproducing recorded information has been composed of a turntable for rotating a disc loaded thereon, a pickup unit for reading out recorded information in the disc that rotates, a transportation mechanism for transporting the pickup unit in a radial direction of the disc, and a mechanism for loading or unloading the disc. In the case of an apparatus that accommodates a recordable discs, the apparatus is provided with a magnetic head. Particularly, such a disc drive apparatus accommodating a recordable disc is provided with a plurality of motors as a driving source for rotating and carrying a disc, for transporting a pickup, and for elevating a magnetic head. However, increasing a number of motors makes an apparatus larger in size and results in increasing a manufacturing cost.
Consequently, it has been practiced that one motor was used commonly for carrying a disc and transporting a pickup or for carrying a disc and elevating a magnetic head.
In a case of a disc drive apparatus utilizing a motor common to carrying a disc and transporting a pickup, for example, the Japanese Patent Application Laid-open Publication No. 2001-325775 discloses that unloading a disc is conducted by changing a motor power transmission route from a transporting system for a pickup over to a carrying system for a disc by means of moving a pickup unit to either an inner circumferential side or an outer circumferential side of the disc.
On the contrary, the motor power transmission route of the apparatus disclosed in the Patent Application Laid-open Publication No. 2001-325775 is essential to be changed over to the carrying system for a disc only when the pickup unit is transported to the outside of an information recording area of the disc so as not to have been changed over to the carrying system for the disc while reproducing the disc. In this connection, a range of movement of the pickup is essential to be set wider, and resulting in a problem such that the apparatus is made larger in size.
Particularly, in a case of a disc contained in a cartridge such as an MD disc, a part of the cartridge is opened so as to expose an information recording area of the MD disc. An objective lens of a pickup unit is made to approach the disc within an opened section of the cartridge. Consequently, the pickup unit disables to be transported because the pickup unit interferes with the cartridge although the pickup unit is attempted to be transported to the outside of the information recording area of the disc in order to change a motor power transmission route over to the carrying system for the disc.
Accordingly, in a case of a disc that is not contained in a cartridge such as a CD disc, a pickup unit enables to be used as a trigger for changing a motor power transmission route. However, the pickup unit disables to be applied for a disc contained in a cartridge as a trigger. A conventional disc drive apparatus that accommodates a disc contained in a cartridge has been equipped with a plurality of motors for rotating a disc, transporting a pickup unit and carrying the disc individually, so that the apparatus was hardly decreased in size or reduced in cost.
On the other hand, providing a motor exclusively for elevating a magnetic head as a driving source makes the apparatus to be decreased in size or reduced in cost harder. Consequently, it is strongly required for such an exclusive motor to be shared with other driving source.